Absolute majority of online poker rooms allow opening several poker tables to play, but even if that prohibited, you may open several poker rooms. You may move between poker tables opened on a screen without overlapping.
It is understood that you should play poker on two tables if you are sure that you can win on one of the table paying less attention to it. If you can on two tables, you may add one more and so on. Sometimes on gambling forums you would meet most desperate poker players who are able "to serve" up to eight poker tables. For sure it is too many. When you move to a large number of tables, you should expect some degradation of results because of lower concentration. Nevertheless, if on one table you win four bets, on two tables you will three bets per table and the total win will increase one and a half, so the game is worth the candle.
If you remember, disconnects in online casino are not dangerous as your bet is stored and you will be able to play it later. In online poker room you are unable to play a deal later as you are not playing along. Therefore, there is created insider disconnect protection in online poker rooms. First of all, in the event of disconnect, the poker player, as a rule, is given some additional time to act. If disconnect during such period is not renewed, it is considered as the player goes all-in with the chips put into the pot by him. In this case the pot is divided in two parts: main pot is a pot that includes all chips put before disconnect (and before one player involuntary went all-in). The second part of the pot is a side pot that includes the chips put by other players upon equalising all-in bet. If a poker player with disconnect has the best poker combination, the players receives the main pot, and the side pot goes to a player with the second best hand. Otherwise, the poker player with the best combination takes both pots.
Unfortunately, some poker players can pretend disconnects in dangerous for them situations trying to protect their investments into the pot. Most often such situation happens in no-limit poker. For example, you have the highest set on the flop, you raise the bets actively and have also the best combination on the turn, the pot is very high, but suddenly for the river you have the third or fourth community card, and your opponent goes all-in. The pot is huge and you must respond not less. What should you do? You do not want to risk large amount of money in order to check if your opponent has gathered a straight, however, it distresses you to give the hardly built pot. There is another way - to disconnect. In such a case you do not need to respond to the opponent's bet and if your combination is better, you will get the whole all-in.
It is understood that such actions are unethical at least, and they are prohibited in all poker rooms. That is why the number of all-ins in disconnects is limited (usually from one a day to several a week). Players with often disconnects are being checked, and their actions become suspicious, such players may be deprived of disconnect protection at all. As the benefit of false disconnects in limit poker is much smaller, many poker rooms provide protection only on the limit or add special tables without protection on the no-limit and pot-limit. There is no disconnect protection in tournaments at all.